RU2285823C1 - Stator for screw gerotor hydraulic machine - Google Patents

Abstract

FIELD: earth drilling, particularly gerotor mechanisms of screw downhole motors used for oil and gas well drilling, as well as screw hydraulic motors and general-duty hydraulic pumps.

SUBSTANCE: stator comprises hollow body, stator shell with inner helical multiturn teeth and liner secured inside stator shell and provided with inner helical multiturn teeth. The liner is made of elastomeric material, for instance of rubber. Stator shell includes two sections with contact end surfaces arranged along central axis thereof and extending through the full shell length. Inner helical multiturn teeth of each section are formed as projections of inner helical multiturn teeth of adjacent section. Contact ends thereof have longitudinal facets welded to each other. Hollow body comprises at least two adapters located at body edges and enclosing ends of two sections. One edge, for instance end, of each section is secured to edges, for instance with ends, of the body and of the adapter by means of annular weld seam.

EFFECT: improved energy characteristics, service life and reliability.

4 cl, 3 dwg

Description

The invention relates to gerotor mechanisms of downhole screw motors for drilling oil and gas wells, to screw pumps for oil production from wells, and also to screw hydraulic motors and general purpose hydraulic pumps.

A well-known stator of the downhole motor DVRZ-176 is used, in which a lining with helical teeth made of elastomer, essentially made of rubber, is vulcanized (magazine "Construction of Oil and Gas Wells on Land and Sea", Moscow, VNIIOENG OJSC, No. 9, 2003, p. 10, fig. 4).

A disadvantage of the known design is the incomplete use of the possibility of increasing the energy characteristics, resource and reliability of the downhole screw motor, increasing the maximum power, the torque on the output shaft in the maximum power mode and the permissible axial load on the drill bit in the wellbore.

The disadvantages of the known design are explained mainly by the cyclic loading of helical teeth made of elastomer in the stator lining, which undergo deformation and bending during planetary-rotor rotation of the rotor inside the stator, which leads to heat generation inside the tooth material.

In this case, the temperature in the elastomeric lining can increase, for example, to 60 ° C, and the increase in interference in the working pair can be, for example, up to 0.05 mm per diameter for every 10 ° C of temperature increase, which leads to a violation of the seal in the working pair and tooth decay in the elastomeric stator lining.

For the known design, there is a limitation between the differential pressure (interturn, on the stator teeth) in the maximum power mode and the interference value of the rotor teeth in the stator teeth, and the pressure drop in the maximum power mode is essentially 10 ... 13 MPa, which does not allow to increase the moment of force on the output shaft in maximum power mode, to reduce the wear rate of working surfaces, does not provide the possibility of working couples working up to large gaps, while the average resource of the working pair does not exceed 250 hours.

A known eccentric screw pump or eccentric screw motor containing a shell (skeleton) 21 with outer and inner surfaces made in the form of a helicoid with a fully lined stator, in which at the end edges 41, 42 there are seals 26 and retaining rings 28, which seamlessly pass into the lining of the elastomer 39 of the metal shell 21 (US 6666668 B1, F 01 C 1/10, 12/23/2003).

The known design is fastened with studs 17, nuts 19 and flanges 12, 15 outside the core 21, and is used in ground equipment, for example, for gerotor screw pumps, where there are no restrictions on the external dimensions.

A disadvantage of the known design is the impossibility of its use in wells, in casing and drill pipes, for example, for multi-start gerotor hydraulic motors for drilling oil and gas wells.

This is explained by the increased diameter of the inlet from the side 44, as well as the outlet from the side 42 of the shell part 21, the seals 26 and the retaining rings 28, which integrally pass into the lining 39 made of elastomer.

For gerotor mechanisms of downhole screw motors placed in oil and gas wells, the use of the known design does not provide significant advantages.

Known stator of an eccentric screw pump containing a shell (core) of the stator 12 with an internal surface made in the form of a helicoid, and a lining 26 of elastomer on the inner surface of the stator 12, in which each of the ends 20 is connected to the flanges 32, 34 by connecting elements (threaded rods ) 40 and detachable clamps 46, 48 with bursting bolts 50, and the stator shell 12 is made with at least one zone of the connector 14 along a helix through its entire length (US 5318416, F 04 С 2/107, 07.06 .1994).

The known design is used essentially in technological blocks of machines - extruders for visco-elastic liquids, for example, when pouring rocket engine bodies into jelly-like solid fuel in order to ensure the safety of the structure in order to reduce pressure before the explosion hazard can develop.

A disadvantage of the known design is the impossibility of its use in wells, in casing and drill pipes, for example, for multi-start gerotor hydraulic motors for drilling oil and gas wells.

This is explained by the increased dimensions in the cross section: detachable collars 46, 48, the diameter of the input and output parts of the casing and flanges 32, 34, as well as seals and protective rings, which seamlessly pass into the elastomeric lining of the casing.

For gerotor mechanisms of downhole screw motors placed in oil and gas wells, the use of the known design also does not provide significant advantages.

A well-known stator of a downhole gerotor machine, including a housing installed in it with the formation of an annular cavity, a working sleeve made in the form of a thin-walled sleeve with an elastomer lining vulcanized to it, having an internal helical surface, as well as an adapter connected to the housing by a threaded connection (RU 2018620 C1, E 21 B 4/02, 08/30/1994).

In the known construction, the annular cavity is isolated from the external environment, the ratio of the thickness of the metal thin-walled sleeve in its middle part to the outer diameter of the sleeve is 0.02 ... 0.09, and the ratio of the radial size of the cavity to the thickness of the sleeve in its middle part is within 0 , 02 ... 0.15, while the sleeve can be made with through holes and connected to the sub with a threaded connection.

A disadvantage of the known design adopted as a prototype is the incomplete use of the possibility of increasing the energy characteristics, resource and reliability of a downhole screw motor containing a known stator, essentially increasing the maximum power, the torque on the output shaft in maximum power mode and the permissible axial load on the drill bit wellbore.

The disadvantages of the known design are mainly explained by cyclic loading of helical teeth made of elastomer in the stator lining, which are subjected to deformation and bending during planetary-rotor rotation of the rotor inside the stator, which leads to heat generation inside the tooth material.

In this case, the temperature in the elastomeric lining can increase, for example, to 60 ° C, and the increase in interference in the working pair can be, for example, up to 0.05 mm per diameter for every 10 ° C of temperature increase, which leads to off-design operating conditions and destruction teeth in the elastomeric stator lining.

For the known design, there is a limitation between the differential pressure (interturn, on the stator teeth) in the maximum power mode and the amount of interference between the rotor teeth in the stator teeth. In this case, the maximum pressure drop (inter-turn, on the teeth of the elastomeric stator lining) in the maximum power mode, for example, on the teeth of the DR-95 engine (produced in the Russian Federation) is 9 ... 14 MPa, see page 8. (Magazine "Construction of oil and gas wells on land and at sea", Moscow, JSC "VNIIOENG", No. 9, 2003, p. 10, Fig. 4).

The disadvantages of the known design do not allow more to increase the torque on the output shaft in maximum power mode, to reduce the rate of wear of the working surfaces, do not provide the possibility of working pairs to large gaps, while the average resource of the working pair does not exceed 250 hours.

Closest to the claimed design is a stator of a screw gerotor hydraulic motor containing a hollow body, a stator sleeve with internal multi-tooth teeth (or with an internal and external surface made in the form of a helicoid) installed in it, and a lining with internal multi-thread screw mounted in the stator sleeve teeth made of elastomer, for example rubber (US 5171138 A, F 01 C 1/10, 12/15/1992).

In the known construction, the stator sleeve 16 is made in the form of a stamped metal tubular shell with internal and external helical multiple teeth (or with an internal and external surface made in the form of a helicoid).

A disadvantage of the known design is the incomplete use of the possibility of increasing the energy characteristics, resource and reliability of a screw gerotor hydraulic motor using the inventive stator, essentially increasing the maximum power, the torque on the output shaft in the maximum power mode and the permissible axial load (per bit) with increasing maximum pressure drop (interturn, on the stator teeth) in maximum power mode.

The disadvantages of the known design are explained by the low stiffness of the stator tubular sleeve within its elastic deformation, its poor weldability with a massive hollow body, which determines the insufficient fatigue endurance (resource) of the stator sleeve to ensure maximum pressure drop (inter-turn, on the stator teeth) at maximum power.

The disadvantages of the known design are also explained by the relaxation of stresses in the material of the stamped metal stator sleeve, which distort the pairing profile of the working rotor – claimed stator pair at the maximum pressure drop (inter-turn, on the stator teeth) at maximum power.

The disadvantages of the known design are also explained by the cyclic loading of helical teeth made of elastomer in the stator lining, as well as the stator tubular sleeve with internal and external helical multiple teeth, which have low rigidity, which undergo high deformation and bending during planetary-rotor rotation of the rotor inside the stator, which leads to heat release inside the tooth material, as well as to the detachment of the stator lining from the stator sleeve.

In this case, the temperature in the elastomeric casing can increase more intensively due to the smaller mass of the rubber casing, for example, up to 80 ° C, and the increase in interference in the working pair can be, for example, up to 0.08 mm per diameter for every 10 ° C temperature increase, which leads to off-design operating modes, essentially does not provide maximum power, moments of force on the output shaft in the maximum power mode and permissible axial load when increasing the maximum pressure drop (inter-turn, on the stator teeth) in the maximum th power.

The technical result of the invention is to increase the energy characteristics, resource and reliability of a screw gerotor hydraulic machine when used as a multi-start screw helical downhole motor using the inventive stator, essentially increasing the maximum power, torque on the output shaft in maximum power mode and permissible axial load by increasing the stiffness of the stator sleeve, the fatigue endurance of the elastomeric plate and the accuracy (straightness) of the channel of the elastomeric LadKom and maximize the differential pressure (inter-track, on the stator teeth) in maximum power mode.

The essence of the technical solution lies in the fact that in the stator of a screw gerotor hydraulic machine containing a hollow body, a stator sleeve with internal multi-tooth teeth is installed in it, and also a lining with internal multi-tooth teeth made of elastomer, for example rubber, fixed in the stator sleeve according to the invention, the stator sleeve is made of two sections with the surfaces of the contacting ends located along its central axis passing through its entire length, internal wines multiple teeth in each section are a continuation of the internal multi-tooth helical teeth of the adjacent section, and its contacting ends are made with longitudinal chamfers connected by a weld, and the hollow body contains at least two adapters located at its edges and covering the ends of two sections, a region, such end, each section fastened to the edges, for example with the ends, the housing and the adapter ring by means of a weld, while in coated with internal helical teeth thickness Δ in the _height of the projections ntovyh teeth and thickness Δ _sn depressions helical teeth are related by: Δ _height = (1,25 ± 0,25) Δ _VI Δ _height and thickness along the projections of helical teeth, and respectively, thickness Δ _sn depressions along helical teeth made within ± 5%.

The hardness of the lining with internal helical teeth made of rubber is 70 ± 3 units. Shore A.

Each section of the stator liner thickness ΔR _ch depressions helical teeth and thickness Δ _sn depressions in coated helical teeth with inner helical teeth made of rubber, are related by: ΔR _ch = (1,618 ... 2,314) Δ _VI.

Each section of the stator liner thickness ΔR _ch depressions helical teeth and the wall thickness of the hollow body _armature ΔR related by: ΔR _cor = (1,618 ... 2,314) ΔR _ch.

Analysis of the reasons for reducing the resource of downhole screw motors shows that the main cause of defects (failure) is the detachment of the elastostomer and the destruction of the stator tooth. The first defect is due to the poor quality of gluing and is, in most cases, industrial.

Moreover, in the known stator design adopted for the prototype, the first and second defects are the result of cyclic loading of the elastomer and the tubular stator sleeve and depend on operating conditions and conditions. The development of these defects is facilitated by high working pressure drops, internal heat generation in the material of the stator elastomeric lining, braking of the working pair during operation, high tightness in the working pair. The increase in the length of the section of the working pairs can significantly reduce the level of contact loads in the engagement of the working pair and prevent premature destruction of the elastomeric stator lining. At the same time, the energy characteristics of the engine, reliability and service life are significantly increased. However, an increase in the length of the rotor – stator working pairs worsens the “passability” of the bottom hole assembly while drilling directional wells.

In the claimed design due to the fact that the stator sleeve is made of two sections with the surfaces of the contacting ends located along its central axis passing through its entire length, the internal multi-tooth helical teeth in each section are a continuation of the internal multi-helical teeth of the adjacent section, and its contacting ends made with longitudinal chamfers connected by a weld, and the hollow body contains at least two adapters located at its edges and covering the ends of two sections, a region, such end, each section fastened to the edges, for example with the ends, the housing and the adapter by means of an annular weld, while a second plate with internal helical teeth thickness Δ _height of the projections of helical teeth and thickness Δ _sn depressions helical teeth are related by: Δ _height = (1.25 ± 0.25) Δ _VP , and thickness Δ _height along the protrusions of the helical teeth and, accordingly, the thickness Δ _VP along the hollows of the helical teeth are made within ± 5%, the stator sleeve rigidity, the accuracy (straightness) of the channels are increased elastomeric stators, for example, d a length of 6 meters, and provides a maximum pressure drop (inter-turn, on the teeth of the stator) in the maximum power mode, which is essentially 22 ... 27 MPa.

In the claimed design due to the fact that the hardness of the lining with internal helical teeth made of rubber is 70 ± 3 units. Shore A, provides increased fatigue endurance (resource) - at least 100 thousand cycles, increased durability: abrasive and in the environment of petroleum products, as well as high elasticity, elasticity and reliability of sealing of the working rotor-stator pair in maximum power mode.

Due to the fact that in each section of the stator liner thickness ΔR _ch depressions helical teeth and thickness Δ _sn depressions in coated helical teeth with inner helical teeth made of rubber, are related by: ΔR _ch = (1,618 ... 2,314) Δ _VI provides increased fatigue endurance (resource) of the stator sleeve, as well as increased maximum pressure drop (inter-turn, on the stator teeth) in the maximum power mode, which is essentially 22 ... 27 MPa.

Due to the fact that in each section of the stator liner thickness ΔR _ch depressions helical teeth and the wall thickness of the hollow body _armature ΔR related by: ΔR _cor = (1,618 ... 2,314) ΔR _ch, technological advantages provided by the strength and tightness of annular welds, and also increases the accuracy of manufacturing, for example, the deviation from the straightness of the channels of elastomeric stators with a length of 6 meters does not exceed 1.5 mm

When using the inventive design of the stator in a downhole motor, its energy characteristics, resource and reliability increase, essentially the maximum power, the moment of force on the output shaft in maximum power mode and the permissible axial load on the bit increase.

When using the inventive design of the stator increases the resource of the working pair of the rotor - stator by 30 ... 40%, and the mechanical speed by 30 ... 5 0% more. Due to the increased resource and mechanical speed, the penetration of the rotor-stator working pair increases by 1.2 times.

Below is the best embodiment of a stator design for a downhole motor for drilling oil wells.

Figure 1 shows a longitudinal section of the stator of a downhole motor.

Figure 2 shows a section aa in figure 1 across the stator and rotor of a downhole screw motor.

Figure 3 shows a section bB in figure 1 across the stator of a downhole screw motor.

The stator of a downhole screw motor comprises a hollow body 1, a stator sleeve 2 installed therein with internal multi-tooth helical teeth 3, and also a lining 4 with internal multi-tooth helical teeth 5 fixed in the stator sleeve 2 and made of elastomer, for example, rubber, shown in FIG. one.

The stator is designed for a downhole screw motor, where pos.6 is the rotor, pos.7 is the axis of the rotor 6, pos.8 is the axis of the stator, and pos.9 is the eccentricity of the rotor 6 installed in the elastomeric lining 4 of the stator sleeve 2, shown in figure 1, 2.

The stator sleeve 2 is made of two sections 10, 11 with the surfaces of the contacting ends 12, 13, and also 14, 15 extending along its entire length 16 located along its central axis 8, the internal multi-helical teeth 3 in section 10 are a continuation of the internal multi-helical teeth 3 of the adjacent section 11, shown in figures 1, 2, 3.

The contacting ends 12, 13 of sections 10, 11 are made with longitudinal chamfers 17, 18 connected by a weld 19, and the contacting ends 14, 15 of sections 10, 11 are made with longitudinal chamfers 20, 21 connected by a weld 22, shown in FIG. 2 , 3.

The hollow body 1 contains at least two adapters 23, 24 located along its edges and covering the ends 25, 26 of two sections 10, 11, and the edge, for example the end face 27, of each section 10, 11 is fastened to the edges, for example, to the end 28, the housing 1 and the end face 29 of the adapter 23 using an annular weld seam 30, shown in figure 1.

An edge, for example an end face 31, of each section 10, 11 is fastened to the edges, for example, with an end face 32, a housing 1 and an end face 33 of an adapter 24 using an annular weld 34, shown in FIG. 1.

The second plate 4 with internal helical teeth 5 35 thickness, Δ _height of the projections 5 and the helical teeth 36 of thickness, Δ _sn depressions helical teeth 5 are related by: Δ _height = (1,25 ± 0,25) Δ _wp and thickness 35, Δ _{the height} along the protrusions of the helical teeth 5 and, accordingly, the thickness 36, Δ _VP along the hollows of the helical teeth 5 are made within ± 5%, shown in Fig.2.

The hardness of the lining 4 with internal helical teeth 5, made of rubber, is 70 ± 3 units. Shore A.

In each section 10, 11 of the stator 37 of the sleeve thickness, ΔR _ch depressions helical teeth 3 and thickness 36, Δ _sn depressions helical teeth 5 in the second plate 4 with internal helical teeth 5 formed of rubber, are related by: ΔR _ch = (1,618 .. .2,314) Δ _int .

In each section 10, 11 of the stator 37 of the sleeve thickness, ΔR _ch depressions helical teeth 3 and the thickness of the wall 38 of the hollow body ΔR _armature 1 are related by: ΔR _cor = (1,618 ... 2,314) ΔR _ch.

In addition, figure 2 shows: pos. 39 - screw chambers between the teeth of the rotor 6 and the teeth 5 of the elastomeric plate 4; figure 1 shows: 40 - the direction of flow of the working fluid (drilling mud).

The stator design when used in a downhole screw motor works as follows: mud flow 40 under pressure, for example, 22 ... 27 MPa in maximum power mode, is supplied through the drill pipe string to the screw chambers 39 between the teeth of the rotor 6 and the teeth 5 of the elastomeric lining 4 and forms a region of high pressure and a moment from hydraulic forces, which leads the planetary rotor rotation of the rotor 6 inside the sections 10, 11 of the stator sleeve with the elastomeric lining 4 fixed in them.

Helical teeth 5 of the elastomeric plate 4 in sections 10, 11 of the stator sleeve undergo complex deformation and bending during planetary-rotor rotation of the rotor 6 inside the stator.

The screw chambers 39 between the teeth of the rotor 6 and the teeth 5 of the elastomeric cover 4 have a variable volume and periodically move along the flow 40 of the drilling fluid, which has a density of up to 1500 kg / m ³ , contains up to 2% sand and up to 5% of oil products.

In the claimed design due to the fact that the second plate 4 with internal helical teeth 5 35 thickness, Δ _height of the projections 5 and the helical teeth 36 of thickness, Δ _sn depressions helical teeth 5 are related by: Δ _height = (1,25 ± 0,25) Δ _vp , and thicknesses 35, Δ _vys along the protrusions of the helical teeth 5 and, accordingly, the thickness 36, Δ _vn along the depressions of the helical teeth 5 are made within ± 5%, the accuracy (straightness) of the channels of elastomeric stators is increased, and increased fatigue endurance (resource ) - not less than 100 thousand cycles, high resistance: abrasive and in Food products as well as high elasticity and a pair of seal reliability working rotor - stator maximum power mode.

The invention improves the energy characteristics, resource and reliability of a downhole screw motor using the inventive stator, essentially increases the maximum power, the torque on the output shaft in maximum power mode and the permissible axial load, while providing an increased maximum pressure drop (inter-turn, on the stator teeth) in maximum power mode, which is essentially 22 ... 27 MPa with a lower level of stress-strain state of elastomeric teeth.

Claims (4)

1. The stator of a screw gerotor hydraulic machine, comprising a hollow body, a stator sleeve with internal multi-tooth teeth installed in it, and also a lining with internal multi-tooth teeth made of elastomer, for example rubber, fixed in the stator sleeve, characterized in that the stator sleeve is made of two sections with the surfaces of the contacting ends located along its central axis, passing through its entire length, the internal helical multi-start teeth in each section are the position of the internal helical multi-teeth of the adjacent section, and its contacting ends are made with longitudinal chamfers connected by a weld, the hollow body containing at least two adapters located at its edges and covering the ends of two sections, and an edge, for example the end of each section , attached to the edges, for example with the ends of the housing and the adapter by means of an annular weld, while in coated with internal helical teeth thickness Δ helical teeth _height of the projections and depressions thickness Δ _sn helical teeth communication by the relation: Δ _height = (1,25 ± 0,25) Δ _VI Δ _height and thickness along the projections of helical teeth, and respectively the thickness Δ _sn depressions along helical teeth made within ± 5%. 2. The stator of a screw gerotor hydraulic machine according to claim 1, characterized in that the hardness of the lining with internal helical teeth made of rubber is 70 ± 3 units. Shore A. 3. Gerotor stator screw hydraulic machine according to claim 1, characterized in that in each section of the stator liner thickness ΔR _ch depressions helical teeth and thickness Δ _sn depressions in coated helical teeth with inner helical teeth made of rubber, are related by: ΔR = _sn (1,618 ÷ 2,314) Δ _VI. 4. Stator screw gerotor type hydraulic machine according to claim 1, characterized in that in each section of the stator liner thickness ΔR _ch depressions helical teeth and the wall thickness of the hollow body _armature ΔR related by: ΔR _cor = (1,618 ÷ 2,314) ΔR _ch.

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